Sergey Biryukov

Samuel Wood (Otto)

In core ticket <a href="https://core.trac.wordpress.org/ticket/28206" rel="nofollow ugc">#28206</a>, the editor was modified to have a Link Text field instead of a Title field.
This plugin adds the Title field back.

Restore Link Title Field

Adds back the missing "title" field in the Insert/Edit URL box in WordPress 4.2

Elio Rivero

This plugin will enable the TinyMCE rich text editor for the title field 
when writing a page or post. Requires jQuery to work, but rather than 
including it with , the plugin will enqueue the jQuery library 
included with WordPress using wp_enqueue_script on the admin area.
There are a couple of style to remove the margin between the title 
label and the TinyMCE editor area, and the padding around the title 
box and the border.
Beware, for this plugin will paragraphise all your titles, so what 
once was a h3 headline in your styles now might be h3 p.
This software is provided without warranty of any kind.

ILC Rich Title

Enables TinyMCE for the title when writing a post or page.

Restore Link Title Field vs ILC Rich Title